24. A project management team is evaluating the causes that might contribute to unsatisfactory performance and quality. Which of the following statements is not true?

A. Normal process variation is attributable to random causes and sometimes also called "white noise".B. Special causes are easier to predict and handle than random causes (also called common causes).C. Special causes are unusual events which are difficult to foresee and often produce outliers.D. A process can be optimized to limit the bandwidth of variations due to random causes.

The correct answer is B.Control charts are used to show whether a repetitive process is “in control” or “out of control” .When 7 consecutive data points are presented on either side of mean, then “process is considered Out of Control” based on heuristic of Rule of Seven.Refer to Page 238 0f PMBOK® Guide 5th Edition

Hi, I passed this test recently, and also choosed B, but Oliver Lehmann wesite tell that it is wrong, correct is A -Normal process variation is attributable to common causes that are part of the system